Illinois can't be accused of rushing to embrace medical marijuana: The first state to allow it did so in 1996, and the General Assembly is only now getting around to approving the idea. Whether it will become law is not clear: It now goes to Gov. Pat Quinn, who has yet to say if he will sign it.

He should, for two big reasons. The first is that cannabis is truly useful for some therapeutic purposes. The second is that this legislation subjects it to tight controls that should alleviate the concerns of skeptics.

Pot has been used by oncologists and other physicians to help patients whose ailments don't respond to conventional pharmaceuticals. In 1999, the federal government's Institute of Medicine concluded, "Scientific data indicate the potential therapeutic values of cannabinoid drugs . . . for pain relief, control of nausea and vomiting, and appetite stimulation."

The system in Illinois would be far stricter than in California, which is notorious for laxity. Patients would not be allowed grow their own, they would be able to get only 2.5 ounces every two weeks, the number of dispensaries would be limited, and patients could get prescriptions only for specific medical conditions -- not including pain and mental illness. California has none of these rules.

Critics say the change will foster more drug abuse -- as though anyone who wants pot right now can't get it. In fact, it will allow patients who have gotten the drug illegally to obtain a clean, predictable version, rather than taken their chances with black-market dealers.

The point of the bill is to offer relief to suffering people who have been beyond the help of other medicines. For Quinn to sign it would be an act of humanity that holds little risk.